For a pupil, a fixed-term exclusion for bad behaviour often means a few days at home, during which you can have a lie-in, play on your computer, watch telly or maybe even go shopping (or shoplifting). With any luck, when you get back to school, the teachers will even forget to chase you up about missing homework.

It used to be pretty much the same at Kingsmead school, in the north London borough of Enfield. But the sanction that has now largely taken its place sounds like every adolescent's worst nightmare.

Wearing your own school uniform, you have to report to a neighbouring school, accompanied by an inclusion officer from your school (and he just happens to be an ex-police officer). You spend the day in the school library. Apart from your lunch break, you work solidly on tasks set by your teachers and are supervised at all times by the inclusion officer. You are away from your peer group and the usual pecking order. And during the day you may have to contend with curious stares from the other school's pupils.

This is "alternative placement provision", a new scheme that has been set up with the help of behaviour improvement programme (BIP) funding from the Department for Education and Skills.

Kingsmead's headteacher, Giles Bird, initiated the scheme, with Janet Cullen, principal of nearby Lea Valley high school, as a way of ensuring "first day provision" - that is, the DfES requirement that pupils who are excluded from school do not miss out on education.

The two schools have set up a reciprocal arrangement to deal with pupils who would otherwise have been temporarily excluded. So far, 20 have gone from Kingsmead to Lea Valley and 32 in the other direction, each for a maximum of three days.

Each school has taken on an inclusion officer to deal with the placements. Nigel Harris, Kingsmead's officer, started in June last year after 30 years in the police force.

When a pupil is given an alternative placement for some misdemeanour, the parents are asked for permission, and Harris collects work from all the teachers the pupil would be having on the day. He meets the pupil at Kingsmead in the morning and escorts him or her by bus to Lea Valley.

Pupils often start to hang back and walk more slowly when approaching the other school, he says. "It's the herd instinct, and they are in a different uniform. It's the same when Lea Valley pupils come here. They don't like standing out or being out of the herd."

Will (not his real name) is a year 7 boy who brought a pellet gun into school and found himself sent to Lea Valley as a result. Back at Kingsmead the next day, he is contrite. He was getting into a lot of fights but now wants to start afresh, he says. When he heard he would have to go to the other school, he says, "I felt shocked and I started to cry a bit. I'd never been to Lea Valley before and I don't know how it is there."

His day at Lea Valley was "really boring. I had to do quite a lot of work and I couldn't do PE or anything." He says he saw only a few other pupils but he felt everyone was looking at him and it made him nervous.

On arrival at Lea Valley, pupils must report to the principal, Janet Cullen. Standing in the office of a headteacher they have never met before, while she addresses them about her expectations of their behaviour in her school, can be daunting. "The talk tightens the screw a little bit - it reinforces that this is not just a jolly outing," says Harris.

Will seems awed by the experience. "You have to call the headteacher ma'am and I'm not really used to that kind of word," he says.

"Ah, yes," smiles Cullen when I ask her about it. "All the female teachers here are addressed as ma'am - it's nicer and more respectful than 'miss'. I remember telling him: 'Fasten up your tie and tuck your shirt in'."

She says her pupils do not like going to Kingsmead, either. One particular grievance is the Kingsmead rule that pupils on the placement are allowed only a sandwich and an apple for lunch, rather than chips.

Only one pupil at each school has been sent back a second time. Cullen says that in over two-thirds of cases, the scheme has nipped their bad behaviour in the bud. Traditional fixed-term exclusions, on the other hand, tend to escalate to permanent exclusion. "Before, we were having about 12 permanent exclusions a year, whereas this year we have only had two," says Bird. Similarly, fixed-term exclusions have gone down from 130 to approximately 20 in the past year (these 20 were cases in which he did not feel it was appropriate to send the pupil to the other school).

As well as improving behaviour, the scheme prevents pupils from missing out on education; if anything, they work harder than they would normally. It is popular with parents, who tend to prefer their children to remain in a school setting. No parents from Kingsmead have refused permission, and only one from Lea Valley.

Bird has sought the opinions of some parents who have had experience with both types of sanction. "Without exception, they much preferred an alternative placement," he says. They also felt it was a more effective punishment.

But for some, the scheme smacks of humiliation and is too harsh. A teacher at another Enfield school that is adopting alternative placement provision says when staff were told, "we were laughing ironically at the thought of some of the kids having to go to another school.

"Behind it, I suppose, was the feeling that it would be humiliating for them. At first I did get the impression they would be taught in classrooms rather than alone in the library, and I was wondering how it would work. But the way it was presented was that it would be such an effective deterrent that it wouldn't happen very often. And it's true that there are a couple of hard cases, boys for whom this would be the next sanction, who have almost reached the begging stage of 'please don't send me there!'

"The school we are going to be paired with is quite close and there's always been an unspoken rivalry between us. So that could be an issue. It would be better if it was another school further out of the area, because then our kids would be less likely to know other kids in the school."

She says some of the staff have mixed feelings about the government's emphasis on inclusion. "You struggle to keep these kids in school, who have caused mayhem and disruption all the way through, and when they get to year 11 you're supposed to pat yourself on the back and say, 'haven't we done well?' In fact, quite a few of us are secretly thinking: 'yes, but at what cost?'"

Another teacher agrees. "Nowadays you can't just kick them out. A lot of things are provided for the kids who are difficult, to encourage them, and it means all your resources are focused on the ones who are causing most problems. The other kids see what they have done and the fact they are still in school, and think: 'they are getting away with it - why shouldn't I?'"

He points out that, from the government's point of view, "alternative placement" is an effective way of getting schools to meet targets for bringing down exclusion rates. "But I don't suppose there's enough money for all schools to do it. As well as having to get the money to pay for someone to escort the pupils, you'd have to find another school to agree to be your partner. If one school has a lot of social problems and a high exclusion rate and the other local schools are better, it would be an unequal pairing. The school with problems could be sending shedloads of kids and it wouldn't work."

Alternative placement provision is just one part of a programme introduced to tackle poor behaviour and attendance and other problems, using dedicated members of staff funded by BIP. Adrian Dow is the behaviour improvement programme manager at Kingsmead. His team includes a learning mentor, as well as Harris, and he can also call on psychologists, educational welfare officers, child guidance workers and others. Kingsmead now has an effective system for "internal exclusion". For instance, while an incident is investigated, pupils continue to work in a special area in the corridor outside the offices of the senior management team.

Dow is evangelical about the need to raise pupils' level of emotional intelligence. His involvement takes the pressure off the heads of year, who are no longer pulled out of lessons to deal with difficult kids; and it means the school's ability to respond to, manage and change bad behaviour has improved radically. Two inspectors who visited recently concluded they had seen nothing in any other school to equal Kingsmead's work on behaviour.

But, says Bird, it is the BIP money that has made this success story possible. His anxiety is that the funding may not continue after 2006. At present, Kingsmead and Lea Valley have been allocated £77,000 each in funding from BIP, with an additional £25,000to cover first day provision.

As a pilot scheme, the alternative placement provision is having a real "ripples in the pool" effect, says Bird. He has had a lot of interest from outside, and at least two other local secondaries are to adopt similar arrangements.

But what about the pupils themselves? "We've done some evaluations in school. All the students said they would rather have a fixed-term exclusion than an alternative placement, which I find interesting," says Bird.

The pupils also overwhelmingly agreed that if they were the victim, they would like to see the perpetrator given an alternative placement; they felt having to attend the other school would be more of a punishment. "Take the shame!" one wrote.